Patent GB-1263436-A (GB)
Title: Improvements in or relating to the stabilization of vehicles
IPC: B66C23/80
Filed: 1970-04-10
Abstract: 1,263,436. Stabilizers for earth working vehicles. POCLAIN. 10 April, 1970 [11 April, 1969] No. 17059/70. Heading B7J. In a method for extending two pairs of stabilizing stays 2, 3 and 4, 5 respectively of a stabilizing device for a mechanical earth working vehicle, the rear stays 4, 5 are extended until they abut fixed stops on the chassis 1, while the front stays 2, 3 are simultaneously extended into positions intermediate between the fully extended and fully retracted positions, the total extension of the front and rear stays having a fixed predetermined ratio to one another. The stays 2, 3 and 4, 5 are attached to rams 6, 7 and 8 respectively, which rams are also attached to the chassis 1 and may be supplied with pressurized fluid by an hydraulic pump 9, the pump 9 being connectible to an output divider 13 via conduits 10, 12 and to each of the pairs of stays 2, 3 and 4, 5 by separate conduits 14 and 15. A three-way slide valve distributer 11 and a two-way slide valve distributer 20 are arranged as in the hydraulic circuit of Fig. 2 and fluid from a reservoir 19 is delivered under pressure to the conduit 10 by the pump 9. The fluid is arrested by distributer 11 in the position shown and returns through conduit 17 and a pressure-responsive valve 18 to the reservoir 19. In this position of distributer 11, the reservoir 19 is closed to the distributer 20. When the valves of the distributers 11 and 20 are pushed to the left, a conduit 12 is supplied with fluid from the pump 9 and the fluid is directed into conduits 14, 15 by the output divider 13 in a fixed ratio. The fluid in conduits 14, 15 enters chambers 6a, 8a of rams 6 and 8 respectively so as to drive fluid out of chambers 6b and 8b to a control valve 21 via conduit 16, distributer 11, conduit 17, distributer 20 and conduit 22. The valve 21 is then moved so as to place chambers 6a, 7a of rams 6, 7 into communication and then excess fluid in conduits 17 and 22 returns to reservoir 19 through the valve 18. The stays 2, 3 and 4, 5 continue to extend until the rear stays 4, 5 reach stops upon the chassis 1 and then ram 8 locks so that no further fluid enters its chamber 8a. The output divider 13 transmits no further fluid through conduits 14, 15 so that the stays 2, 3 take up an intermediate position of equilibrium. The distributers 11 and 20 are returned to their initial positions so as to isolate the chambers 6a, 7a of the rams 6, 7 and thus lock the stays 2, 3 in their equilibrium position. The stays are retracted by drawing the slide valve of distributer 11 to the right and that of distributer 20 to the left. Then fluid fed through conduit 10 passes into conduit 16 and into control conduits for non-return valves 24 in conduits 14, 15. From conduits 16 fluid is fed into chambers 6b, 8b to retract rams 6, 8 and to drive fluid from chambers 6a, 8a via open valves 24 and then into conduit 12 via conduits which by-pass the output divider 13. No fluid can pass into chamber 7b since the valve 21 is positioned to prevent communication between chambers 6a, 7a and thus to prevent discharge of fluid from chamber 7a. Fluid passes from conduit 12 to conduits 17, 22 and moves the valve 21 to place chambers 6a, 7a into communication again and thus permit retraction of ram 7.